<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div id = "app">
        <h1 v-if="type === 'A'">A</h1>
        <h1 v-else-if="type === 'B'">B</h1>
        <h1 v-else>who</h1>
    </div>

<script src="https://cdn.jsdelivr.net/npm/vue@2.5.16/dist/vue.js"></script>
<script>
    var vm = new Vue({
        el: "#app",
        data:{
            type:'A'
        }
    });
</script>

</body>
</html>